[GeorgeSmooth]

Just a quick update. I fitted the catless AE Exhaust today as I was still on a stock exhaust with cats and my word did it make the world of a difference. We did not tune the car further for more boost as the exhaust was a restriction creating major back pressure. The car revs far smoother now at the top side making the 6000-7000rpm noticeably quicker. We tried a more aggressive timing map but the car starting knocking so I would say that slightly before this boost point and on race gas is a requirement.
Next weeks goal is to tune a map for the car using race/meth at 20psi and hitting the dyno. At this stage and from what we have seen the stock fueling system will handle the fueling always keeping in mind its summer here and the air is less dense.
In the two odd weeks and 1500km I have had the car with the RB Turbos it has not leaked a drop of oil or water from the turbos which is a testament to the quality of work in these turbos.

[klipseracer]

Originally Posted by GeorgeSmooth

Just a quick update. I fitted the catless AE Exhaust today as I was still on a stock exhaust with cats and my word did it make the world of a difference. We did not tune the car further for more boost as the exhaust was a restriction creating major back pressure. The car revs far smoother now at the top side making the 6000-7000rpm noticeably quicker. We tried a more aggressive timing map but the car starting knocking so I would say that slightly before this boost point and on race gas is a requirement.
Next weeks goal is to tune a map for the car using race/meth at 20psi and hitting the dyno. At this stage and from what we have seen the stock fueling system will handle the fueling always keeping in mind its summer here and the air is less dense.
In the two odd weeks and 1500km I have had the car with the RB Turbos it has not leaked a drop of oil or water from the turbos which is a testament to the quality of work in these turbos.

great to hear... lets see numbers!! When do you plan to put on a tune we can all relate to?

[Aridk]

Did you do a dyno with the stock turbos just for comparision?

[enrita]

Originally Posted by GeorgeSmooth

Just a quick update. I fitted the catless AE Exhaust today as I was still on a stock exhaust with cats and my word did it make the world of a difference. We did not tune the car further for more boost as the exhaust was a restriction creating major back pressure. The car revs far smoother now at the top side making the 6000-7000rpm noticeably quicker. We tried a more aggressive timing map but the car starting knocking so I would say that slightly before this boost point and on race gas is a requirement.

stupid question maybe but how do you notice when the exhaust is building too much back pressure? can you see this in some parameter in logs?

[GeorgeSmooth]

Originally Posted by klipseracer

great to hear... lets see numbers!! When do you plan to put on a tune we can all relate to?

Boost is boost so in theory all tunes are very close. There are a lot of people using both Procede and JB on the purchase list so I am sure in the next month we will be seeing many sheets. At the moment I us to make 375whp with hood closed in a 38 degree celsius day at 5500ft altitude with 18 odd psi. I will tune the car to make 475whp which should be achievable at around 20psi in the same conditions if my bum dyno is correct.

Originally Posted by Aridk

Did you do a dyno with the stock turbos just for comparision?

I live at 5500ft altitude so my figures can only be compared to Colorado figures but will put up a boost to boost comparison when I get around to it.

Originally Posted by enrita

stupid question maybe but how do you notice when the exhaust is building too much back pressure? can you see this in some parameter in logs?

You can physically measure the back pressure in the exhaust. In my case we started measuring the affects of the stock exhaust with stock turbo on high boost. At that stage I had AR Downpipes that had the oxygen sensor bungs welded in the wrong place so we welded correct ones and had spare bungs. So we made a fitting that joined a pressure pipe to a pressure gauge and did our measurements on the dyno. The results where quite alarming with the pressure in the exhaust going from 5psi to 6.5psi with a boost increase of 1bar to 1.2bar. At 1.4bar it jumped to 10.5psi which meant the exhaust resistance was growing exponentially.
With the RB's on 1.3bar boost the resistance was over 13psi and now with the AE exhaust it feels like it has dropped substantially as the car is pulling much better although it is not tested yet. Keep in mind with the more power of the RB's there are far more burn cycles per second to push out the exhaust.

[enrita]

Thanks George, you do have a lot of nice sensors :-) i just putt 100Cell cats so i was wondering a bit about back pressure. Hopefully soon (when the snow melts away...) we will be able to compare times and dyno power .

[dlbrooks18]

Originally Posted by GeorgeSmooth

Boost is boost so in theory all tunes are very close. There are a lot of people using both Procede and JB on the purchase list so I am sure in the next month we will be seeing many sheets. At the moment I us to make 375whp with hood closed in a 38 degree celsius day at 5500ft altitude with 18 odd psi. I will tune the car to make 475whp which should be achievable at around 20psi in the same conditions if my bum dyno is correct.



I live at 5500ft altitude so my figures can only be compared to Colorado figures but will put up a boost to boost comparison when I get around to it.



You can physically measure the back pressure in the exhaust. In my case we started measuring the affects of the stock exhaust with stock turbo on high boost. At that stage I had AR Downpipes that had the oxygen sensor bungs welded in the wrong place so we welded correct ones and had spare bungs. So we made a fitting that joined a pressure pipe to a pressure gauge and did our measurements on the dyno. The results where quite alarming with the pressure in the exhaust going from 5psi to 6.5psi with a boost increase of 1bar to 1.2bar. At 1.4bar it jumped to 10.5psi which meant the exhaust resistance was growing exponentially.
With the RB's on 1.3bar boost the resistance was over 13psi and now with the AE exhaust it feels like it has dropped substantially as the car is pulling much better although it is not tested yet. Keep in mind with the more power of the RB's there are far more burn cycles per second to push out the exhaust.

Good info, thanks!

[Aridk]

George could you just enlighten me on what you mean by the oxygen sencor beeing in the wrong place on the AR dp´s? and wrere did you pleace them now?

In another post you mentioned you had driven 1500 km so far, so how is it as a daily driver-citytraffic, is it just as dogcile as with the oem turbos?

[GeorgeSmooth]

Originally Posted by Aridk

George could you just enlighten me on what you mean by the oxygen sencor beeing in the wrong place on the AR dp´s? and wrere did you pleace them now?

In another post you mentioned you had driven 1500 km so far, so how is it as a daily driver-citytraffic, is it just as dogcile as with the oem turbos?

AR had originally sent me a set of DP's that had the oxygen sensors in the wrong place due to a mistake of a ex employee. I repaired that set of DP's by putting new wholes where they should have been. AR design sent me a brand new set free of charge which I fitted once I changed the turbos and they worked perfectly without modifications required or anything.
The car responds the same as with the stock turbos on part throttle around town driving. In no way does it feel like there is any additional lag.